Anybody run a GS with no cat?

[ARicci6792]

If so is it even worth it on a n/a? Did yous notice ANY gains at all? And how do you think the GS would sound without a car, resonater and a muffler (ebay )? Thanks alot

 

[viperlp01]

Well alot like a honda to be honest.. Eliminate the cat and have one resonator with a muffler.. That might work but i think the 420a is a little raspy engine

 

[ARicci6792]

ehhhh =/ thats what i dont want
before, i eliminated the resonater and muffler and had straight pipes on it...bad choice..had to get a new muffler
are there any good resonaters i could use on there to keep it down a bit?

 

[92blutalon]

With a non turbo you need back pressure with a turbo no back pressure is needed

 

[VelocitàPaola]

With a non turbo you need back pressure with a turbo no back pressure is needed

That's a fallacy. Back pressure isn't beneficial almost always.

 

[jericho777]

Well alot like a honda to be honest.. Eliminate the cat and have one resonator with a muffler.. That might work but i think the 420a is a little raspy engine

+1 my son says it sounds likea v-tech

 

[JD98GSX]

When I was running my GS I bought the Megan exhaust manifold, downpipe, and cat delete pipe, and left the factory cat-back exhaust system. It ran fineish for a few houndred miles, Of course the check engine light came on but it had alittle more responce it felt like. Then the wear and tear took its toll and the car started running like crap. As stated before a N/T need BP keep that in mind. You would be better of buying a "Hi-Flow" Cat. and to boot it didn't sound that great.

 

[Locke]

I don't know why people ever believed this, but 20 some years later people are still going on about how N/A cars need backpressure, and they're just as wrong now as they were then.
http://www.dsmtuners.com/forums/fre...8578-exhaust-straight-scoop-backpressure.html

 

[420a_turbo]

I burnt valve seals within 10,000 miles both times I deleted my cat N/A. Now Im boosted no issues, but the pro's did tell me that the Cat helps save your seals' life. Something about the converter trapping the heat in the exhaust, while no cat the exhaust gets trapped in the header(When the car is off) and ruins the valve seals on the hot side. I dunno if its true, but my machine shop knows their stuff and I believe them. Haven't had any issues since I went boost with no cat, but had issues with no cat N/A

 

[Locke]

That particular myth stems from the 70's, when catalytic converters were being phased in, and leaded fuels phased out. People would pump unleaded fuel into their pre-cat-era vehicles which had soft metal valve seats. With no lead in the fuel, the hot exhaust valve seats were hammered and worn - the process is known as valve seat recession.

People, older folk in particular, often didn't know exactly WHY this happened, but only knew that their older cars that had no catalytic converters were having valve seat issues all of a sudden, so they assumed that no-cat = poor valve seat life. The cat had nothing to do with this, rather their unknowing use of the wrong fuel in pre-cat vehicles.

Consider the tens of thousands of vehicles driving around today that are either pre-cat-era or have had their cat's removed that are racking up hundreds of thousands of miles with nothing more than normal wear-and-tear.

 

[eclipsetuner23]

all i know is i put an ebay headers back exhaust with a test pipe on my n/t and now my car is knocking!

 

[Choch1]

^Your exhaust back pressure is NOT the reason you car is knocking. facepalm Just a guess, but did you do some redline pulls after you put the exhaust to see how it sounds, on your 420a, with 100k+ miles? Blame it on no back pressure though. Bahaha

 

[RoninEclipse2G]

With a non turbo you need back pressure with a turbo no back pressure is needed

I know Locke already commented on this, but I really need to repost something that I said in another thread

I really hate when people make that mistake.

Backpressure is ALWAYS bad, it means that the exhaust is getting bottlenecked somewhere it shouldn't and is getting pushed BACK (hence the name backpressure) up the exhaust stream. Turbos and cats cause backpressure. Crush bent piping causes backpressure. A banana shoved up the tailpipe causes backpressure. In a perfect world you don't want any backpressure, period.

What you DO need is piping that isn't so big that it hurts your exhaust VELOCITY. If your exhaust is too big the flow actually slows down and you lose the negative pressure waves that actually sucks the exhaust out of the cylinders. That effect is called scavenging. High end NA tuners work very hard to use proper pipe sizing and runner lengths for their exhaust systems because it can actually make quite a big difference on a high strung engine.

When you run a turbo you don't worry too much about scavenging because the boost more than makes up for the fact that 99% of turbo manifolds are unable to take advantage of it.

So remember kiddies, it's not backpressure that you need, it's proper exhaust velocity and scavenging

Oh and running without a cat on a 420a will sound like a big honda with a fartpipe. High flow cat or an extra resonator is the way to go. I happen to like breathing so for me it's a high flow

 

[ARicci6792]

damn with everyones horror stories of removing cats on a n/a, i think ill just stay away from that ..ive decided to try and sell my car, just to see what offers i can get, hopefully i can find a cheap gst/gsx/tsi somewhere local

 

[jericho777]

ebay headers and a test pipe no cel runs great. Is sounding like a Honda really that offensive?

 

[eclipsetuner23]

it does sound really raspy and i dont like it! i want a more deep sound but im rebuilding my engine for turbo so any info on exhaust for that?

 

[Locke]

When you add a turbo, the exhaust note will soften noticably. A turbocharged car with no cat will sound nothing like a NA car with no cat. A turbo makes for a pretty decent muffler.

This is off-topic though, you should start a new thread.

 

[bmxunderground]

My N/A car has headers, hi flo cat (fake a$$ obx thing) and resonated cat back and sounds great. No fart can notes here. My turbo however didn't really sound right, did sound a little raspy, dunno why, ended up just installing a glasspack (sp?) and turbo muffler to quite things down. Gonna say F it though when I finish my motor build and use 3.0 pipe all the way back.

 

[ilco187]

i got a 96 neon r/t with the 420a and its all strait pipe from the cheap header back, my god it is louder than a honda, really i put them to shame.

this is what it sounds like

YouTube - Stupid ricers

 

[jacobevan611]

^Your exhaust back pressure is NOT the reason you car is knocking. facepalm Just a guess, but did you do some redline pulls after you put the exhaust to see how it sounds, on your 420a, with 100k+ miles? Blame it on no back pressure though. Bahaha

I have a 420a with a header no cat and cat back with 70000 miles and I do alot of redline pulls is that bad? I've never hit rev limited I just sometimes shift at 7k

 

[Project2G]

haha nice video

 

[Diamondrev]

I have a 420a with a header no cat and cat back with 70000 miles and I do alot of redline pulls is that bad? I've never hit rev limited I just sometimes shift at 7k

The 420a is known for having thin, weak, engine bearings. yours will go out soon if you continue to redline. KNOCK KNOCK KNOCK

 

[jacobevan611]

thAnks alot. What is the highest I can rev where it is still safe?

 

[Diamondrev]

thAnks alot. What is the highest I can rev where it is still safe?

I wouldn't go past 6000rpms. thats where your powers at anyways, but still if you start knocking like I did, just rebuild the bottom end with built internals. get the crank machined down so you can get bigger bearings.

 

[rshissler]

im runnin a pacesetter 4-2-1 header, 2.5" test pipe, and a 2.5 ebay exhaust that was on the car when i bought it. I have no issuses at all.